symbol vs identifier

symbol and identifier both are nouns.

Word	Noun	Adjective	Verb	Adverb
symbol	Yes	No	No	No
identifier	Yes	No	No	No

As nouns, identifier is a hyponym of symbol; that is, identifier is a word with a more specific, narrower meaning than symbol:

symbol: an arbitrary sign (written or printed) that has acquired a conventional significance
identifier: a symbol that establishes the identity of the one bearing it

symbol (noun)	identifier (noun)
something visible that by association or convention represents something else that is invisible	a symbol that establishes the identity of the one bearing it
an arbitrary sign (written or printed) that has acquired a conventional significance